Field
This invention relates generally to the use of protective casings for insulating standard electrical cable connectors and more specifically to an insulative sheath for encasing a live end of an electrical cable such as a jumper cable.
Electrical cables are used in a variety of different ways in today's society. Commonly, an electrical cable comprises two connectors disposed at opposing ends thereof and an insulative casing to protect the conductive cable itself. Oftentimes, it can be dangerous when one of the connectors of a cable is allowed to lay loosely about while the other connector is coupled to a power source.
This is a particular concern in the context of jumper cables which are used to assist in the starting of a vehicle which has a dead battery or other malfunction of the starter system. As a form of electrical cables, jumper cables comprise a pair of insulated cables with attached connectors used as a temporary connection to transfer energy from a charged battery to a discharged battery.
Due to the large number of motor vehicles which depend upon batteries for engine ignition, the use of jumper cables is very common. Unfortunately, however, inherent dangers of using jumper cables have not been adequately addressed. Further, many of those using jumper cables are not adequately trained in proper safety procedures. As a consequence, many injuries occur to unsuspecting jumper cable users who are unaware of the hazards involved in jump starting a vehicle. For example, statistics show that approximately five percent of the more than 40,000 people who lose their sight annually are the victims of battery explosion accidents. This figure does not take into account the number of people that suffer minor injuries in unreported accidents.
In 1978, a study entitled Battery Explosion Tests and Labeling, Dot Hs-803 665, was completed pursuant to a research contract sponsored by the Federal Department of Transportation. This study was done by the Society of Automotive Engineers, Inc. in concert with a task force made up of persons from the Society of Automotive Engineers (SAE), technical committees on electrical distribution systems, including representatives of manufactures, government and public users. As a part of this study, SAE reviewed and analyzed data regarding reported battery explosion and related accidents which was provided by the U.S. Consumer Product Safety Commission.
The government sponsored study revealed that most explosions are caused by a spark or flame or similar ignition source from outside the battery. According to the report, the ignition source must be placed in an flammable zone of venting hydrogen, which occurs within approximately one to two inches of the point of exit of the gas from the battery's ullage. DOT report, pages 2-13. Upon ignition, the flame propagates into the interior of the battery cell, causing detonation of the contained hydrogen-rich mixture. Battery acid encasement fragments are blown into the face of the unsuspecting victim.
In the typical battery explosion, the igniting shower of sparks is caused by connection of booster cables to the battery terminals. As the circuit is closed by attachment of the terminal, very high currents attempt to bridge the comparatively high resistance area of the contact between the clamp and terminal, thereby causing intense, localized heating. This results in melting and boiling of the mated metallic surfaces, causing white hot, molten metal particles to be ejected. If these fall into the ignition region of the cells, explosion is likely. This condition of molten sparks is much greater when the booster cables are improperly reversed or cross-connected between two twelve volt batteries, as is often done by inexperienced users, thus creating an electrical equivalent of a 24 volt, direct short circuit. The commissioned study revealed that 98.6 percent of the studied battery accidents could be traced to hydrogen gas ignition. Id. pages 2-18.
Responsive to this problem, a number of structures have been developed and marketed wherein an insulative cover or bonnet is provided. For example, applicant is aware of the following U.S. patents, which serve as background references only:
______________________________________ Inventor U.S. Pat. No. ______________________________________ Schulte 4,944,685 Mueller 1,965,151 Woodring 3,853,285 ______________________________________
The Woodring and Mueller patents disclose insulative covers formed of rubber or other suitable, flexible insulating material which substantially covers the electrical connector at the end of a standard electrical cable. Similarly, the Schulte patent discloses a protective bonnet which, when not in use, may remain attached to the electrical cable to prevent loss thereof. While each of these patents may help somewhat in preventing occurrence of the problem above mentioned--that of hydrogen explosion--there are still problems associated therewith. For example, none of these patents discloses or teaches a structure or method for maintaining two related electrical cable connectors on a standard set of jumper cables in a separated position. Once in a properly separated position, the tendency of jumper cables to spark and ignite as described above, is substantially lowered.
Furthermore, these prior art patents have inadequate structures for maintaining the protective or insulative covering in place over the connector. In the Schulte patent, the connector is held in place within the protector by opposing surfaces pressed together, one surface comprising a hook fastening material and the opposing surface comprising a loop material. The Mueller and Woodring patents disclose insulative bonnets which are maintained over the connector and/or electrical cable associated therewith only by frictional means. Whether the protector or bonnet is held in place about the electrical connector by frictional or hook and loop means, there remains a substantial danger that the protector or bonnet will become dislodged, thereby leaving the electrical connector exposed.
Therefore, there exists in the art a legitimate need for a protective covering for electrical connectors, specifically for use with standard jumper cables, which 1) protect and insulate the electrical connector, 2) provide a means for securing the electrical connector within the covering, thereby minimizing the risk of the electrical connector becoming dislodged from the covering, and 3) maintain the electrical connectors of two separate cables which makeup a standard set of jumper cables in a separated position to minimize the risk of hydrogen explosion.